Thermostatic control apparatus



A. D. HORNE.

THERMUSTATIC CONTRGL APPARATUS.

APPLICATION man MAY 6,1922.

42434542. l K Patented Nov. 7, 1922..;

2 SHEETS-SHEET l.

A. D. HORNE.

THERMOSTATIC CONTROL APPARATUS.

APPLICATION FILED IIIAYs, 1922.

l 434,542, l 2 Patente Nov. 7,- 11922.

2 SHEETS-SHEE] Z.

Patented Nov. 7, i922.

Sllitillti rf [t V@ t. ll

ALEXANDER DEVAR HDRNE, 0F GLASGOW', SCGTLAND.

THERMSTTIC CONTROL AFFRTUS.

application mear/ray e, 192e. serial No. assess.

-an expansible element enclosed within an outer tubular member or casing and consisting of a closedcorrugated tube wholly or partially filled with expansible liquid.

ln such apparatus as heretofore commonly employed, the liquid illed corrugated eX-l pansible element is loosely mounted in the outer tubular member or casing andy is adapted, on the attainment of a predetermined temperature, to close avalve, but, the arrangement is found, in practice, to be unsuitable when working at high pressures b'ecause the expansible element tends to buclrle, particularly if the temperature at which the valve closes is exceeded to any appreciable extent, .thereby detracting from the accuracy of the apparatus.

@ne object of the 'present invention is to overcome this tendency/for the elementto buclrle when working at high pressures and, to the attainment of this endl provide an improved thermostatic control apparatus, of

the type specified, wherein the liquid iilled corrugated expansible element and the surrounding tubular member or casing are in close (that is metallic) contact with one another so as to prevent lateral displacement of the element whilst admitting free axial expansion and contraction thereof. Another object is to provide a self contained expansible element with al suitable liquid therein and a third object is to provide an improved thermostatic control apparatus with the expansible element as part thereof.

l find from experiments ythat olive o il and castor oil, are specially suitable for use as liquids for filling the expansible elements. @live Oil is effective over a wide range of temperatures and is best employed as the expansible medium in connection with thermostats wherein the valve is to be closed at some temperature between, say, o F. and F. Castor oil, on theother hand, isbest suited to high temperatures, say above 100 F. llt is advisable vto boilthe castor oil before lling same into the element in order to drive off any light volatile oils which may be present.

ln the case of an element intended to operate at temperatures not exceeding 100O F., the liquid, preferably olive oil, may conipletely lill the element at atmospheric temperature but with an element intended for temperatures above 1GO@ F., it is better that the liquid, preferably boiled castor oi'l, should only partially fill the same at atmospheric temperature thus providing for a certain amount of idle expansion of the liquid independently of the eifective expansion of the element which first occurs when the temperature to which the element is subjected approximates (l0O ltr-20 F. lower than) that at which the valve is toV close. Thiais easily ensured by first illing'the tubular element, then heating it to a ternperature of lO-QOO F. below the minimum working temperature for which it is to be used so as to expel surplus liquid, and, finally, hermetically sealing the element whilst inthe hot state. By working temperature is meant the temperature at which the thermostaticvalve of the apparatus is to close.

rlhe invention is illustrated, by way of eX- ampleon the accompanying drawing whereon i Fig. l is a view of an ordinary thermostatically controlled valve showing the improved thermostatic element in position.

Fig. 2 is a similar view of a radiator control valve with the improved thermostatic element in position.

Fig. 3 is a similar view of a steam trap with the thermostatic element in position.

Fig. l is a sectional elevation of one form or construction of the thermostatic element.

Fig. 5 shows, in vertical section, a modiiied construction of therm'ostatic valve. Fig. 6 is an elevation of the indicator, Fig. 5.

ln Figs. l, 2 and 8, A denotes the casing of the apparatus, B the valve, C the valve seat, D the adjusting screwE the cap there- 1, for, F the spring which opens the valve, and

G a loose piston or plunger through which the expansion ofthe element/X (hereinafter referred to) is communicatedito the valve.

rlhe expansible element X, asbest seen in F ig. Li, consists of a spirally corrugated tube l closed, at one end, by a plate or equivalent 2 to form a container for a liquid 3, and

.35 moves the valve towards its seat C. The

also closed, at its other end, by a cap 4. The cap 4 is screw threaded to correspond to the corrugations of the tube and is welded, sweated, or soldered in place in the'tube 1. A hole or passage 5vis made through the plug to allow excess liquid to'escape when spring F.

fthe tube H is rigidly attached to the casing s the element l expands in the tube H it moves the plunger G andv valve B against the action of the spring F'until, when a certain predetermined temperature (which is capable ot regulation by means of the adjusting screw D) is reached the valve closes on its seat C. Any further expansion of the element is taken up by the weak spring I. When the temperature drops and the element contracts again the valve is reopened by the In the radiator contrrl trap shown in Figs. 2 aIT 3 respectively the tube H is slidably mounted in the casing A and the valve B is movable therewith. Under expansion of the element the tube moves to the right in the figures and in so doing valve closes when a certain temperature is reached as determined by the position of the adjusting screw D In thev arrangement shown at Fig. 5 the expansion of the element X causes the tube valve and steam H to move downwards and gradually close -the valve B which is connected to the tube by the hollow stem J The temperature at which the valve automatically closes is regulated by a screw D having an indicator hand wheel L. The screw engages the upper end of the plunger rod Gbearing against the top of the element X. The pointer M indicates the extent to which the hand wheel requires'to be turned for the different temperatures.

' Having now fully described my invention what I claim and desire to secure by Letters Patent is A thermostat, including a valve casing having a valve seat therein, a protective tube mounted in the casing, a thermostatic element mounted in said tube and directly contacting therewith, said tube thereby confining said clement .and causing the same to move in alignment and incontact with the casing to guide the element in the operation of the latter and prevent buckling, a plunger slidably mounted in one end of the tube and projecting beyond the end thereof, a valve slidably mounted on the end of the plungera and resilient means between the end of the plunger and the valve for holding the valve in projected position on the plunger, whereby in the expansion and contraction of the thermostatic element, the valve Will be moved toward or away from theseat in the casing, and the resilient means will take up a further movement of the plunger after the valve is seated.

In testimony whereof I aliX my signature in presence of two Witnesses.

ALEXANDER DEWAR HORNE.

IVitnesses :k

KATE WALKER,

MARY GREEN. 

